In many environments, computers usually remain on for many hours at a time. Special-purpose computers, such as file servers, are usually never turned off. Therefore, peripherals such as monitors are also turned on for extended lengths of time.
In the case of older monitors, this situation creates a potential for damage to the monitor. If left turned on and displaying an unchanging image, the monitor may develop burn in. The image displayed on the monitor may burn itself in to the monitor permanently, such that a ghosting of the image is always visible. In the case of newer monitors, the potential for burn in is slight. However, potential for unauthorized viewing of information on a monitor of a computer may occur. For example, if a computer is left on while a user goes to lunch, any sensitive information on the computer screen is easily read by even casual passers by. This leakage of sensitive data may be more serious than the physical damage resulting from burn in.
A solution to this problem is the screen saver program, such as that available commercially as After Dark, from Berkeley Systems of Berkeley, Calif. When the operating system detects that the user has not utilized an input device, such as a computer keyboard or a mouse or other pointing device, for a predetermined length of time, the operating system activates the screen saver program.
The screen saver program may blank out the screen, so that information the user had been working on is no longer displayed on the screen, and so that burn in is prevented. Alternatively, the program may display a changing sequence of images, such as a scrolling marquee. In a further alternative, the program may cause the computer monitor to enter a power conservation mode, which causes the monitor to turn off its display.
The prior art operating system activation of such screen saver programs assumes that a user is not using the computer if the user has not utilized an input device for more than the predetermined length of time. This is not always the case. For example, a user may be scanning a hard disk drive (HDD) for errors, or defragmenting the HDD, processes which can take several minutes, and during which the user typically does not utilize the input device. In these situations, the screen saver may erroneously be activated, because a period of input device inactivity has occurred. This may be an annoyance for the user, because such computer programs typically display status information on the screen, which the user may want to view. In addition, the activation of the screen saver may also cause the error-checking or the defragmenting of the HDD to stop. In some cases, the activation of the screen saver program may potentially corrupt the HDD. Finally, some screen saver programs significantly utilize the processor of the computer, which may make the defragmenting or other process also being executed by the processor run less efficiently.
Therefore, there is a need for operating system to prohibit activation of a screen saver program in response to detection of storage device activity. Such operating system activation of a screen saver program should thus allow for the possibility that a user of the computer may be performing an activity that does not require input device inactivity. Such operating system activation of a screen saver program should activate only if the user is truly not utilizing the computer.